Electrical connection with tapered plug



Nov. 4, 1958 1-. A. FELTON ELECTRICAL CONNECTION WITH TAPERED PLUG FiledDec. 21. 1955 3 Sheets-Sheet 1 FIG.

FIG. 3

FIG. 2

INVENTOR THOMAS "A. FELTON ATTORNEYS 3 Sheets-Sheet 2 INVENTOR THOMAS A.FEL TON ATTORNEYS T. A. FELTON ELECTRICAL CONNECTION WITH TAPERED PLUGFiled Dec. 21, 1955 Nov. 4, 1958 FIG 4 W ME FIG. 5

Nov. 4, 1958 T. A. FELTON ELECTRICAL CONNECTION WITH TAPEZRED PLUG- 5Sheets-Sheet 3 Filed Dec. 21, 1955 INVENTOR THOMAS A. FELTON ATTORNEYStates ELECTRICAL CONNECTGN WITH TAPERED PLU Application December 21,1955, Serial No. 554,447

Claims priority, application Great Britain January 8, 1955 Claims. (Cl.339270) The present invention relates to a new type of electricalconnector and in particular to an electrical connector suitable forcarrying a very high amperage current and for withstanding hightemperatures.

The supply of electric current to apparatus such as electric arcfurnaces for producing calciumcarbide, ferroalloys, phosphorus and thelike frequently involves the use of flexible conductors in theelectrical circuit in a position adjacent to the electrodes. Suchconductors, which normally consist of composite cables having at leasttwo and preferably numerous strands, have to be capable of carrying avery high amperage current, for instance up to 300,000 amperes in asingle electrode single phase furnace, and may be water-cooled to enablethem to withstand the high temperatures to which they are subjected byreason of their proximity to the furnace. A flexible conductor of thistype is advantageously provided with a connector which enables it to beeasily disconnected from the current supply at one end and/or from theelectrode assembly at the other end when the furnace is not inoperation. The provision of connectors for this purpose has always beena matter of extreme difliculty particularly where it is necessary toprovide internal and external water cooling for the flexible conductoras well as for the connector. To ensure the eflicient conduction of thehigh amperage current through the con nector it is necessary for thecontacts to be locked together under pressure, for instance by means ofa number of bolts, and the connectors employed hitherto have beensubject to failure amongst other reasons as a result of stresses andstrains being set up on the heat expansion of the metal locking means,giving rise to failure of one or more of the securing bolts.

It is an object of the present invention to provide an electricalconnector which allows eflicient conduction of a high amperage electriccurrent and which is capable of withstanding high temperatures. It is afurther object of the present invention to provide a water-cooledelectrical connector having these properties.

Accordingly, the present invention for an electrical connector forconnecting two conductors at least one of which is a flexible compositecable conductor comprises a contact sleeve adapted to be conductivelyconnected to one of the conductors, a contact plug adapted to fitclosely inside the contact sleeve, the contact plug having alongitudinal bore of regular cross-section which tapers from each end toa minimum cross-section substantially in the centre of the length of theplug and being split longitudinally into at least two segments, eachsegment being adapted to be welded or brazed to part of the otherconductor which is a composite flexible conductor, a tapered membershaped to fit the taper at one end of the bore, a second tapered membershaped to fit the taper at the other end of the bore, and means forscrewing the two tapered members together when in position in the borewhereby the segments of the contact plug are forced outwards against theinner surface of the contact sleeve, thereby making the electricalconnection.

The term brazed is used to include the fixing of the plug to theconductor by the fusion of any suitable metal or alloy.

The invention is further illustrated with reference to the accompanyingdrawings.

Figure l is a longitudinal section through one embodiment of theelectric connector of the present invention.

Figure 2 is a cross-section along the line 2-2 in Figure 1.

Figure 3 is a cross-section along the line 33 in Figure 1.

Figure 4 is a longitudinal section through a second embodiment of theelectrical connector of the present invention.

Figure 5 is a cross-section along the line 5-5 in Figure 4.

Figure 6 is a longitudinal section through a water cooled electricalconnector according to the present invention.

Figure 7 is a cross-section along the line 7-7 in Figure 6.

Figure 8 is a view in direction of arrow T in Figure 7.

In Figure 1 a rectangular projection X, from the contact sleeve 0, ispermanently connected, e. g. by welding, to the conductor C. The contactplug Q is shaped to fit closely inside the contact sleeve 0 and has alongitudinal bore S of circular cross-section. The bore tapers from eachend to a minimum diameter substantially in the centre of the length ofthe plug. The contact plug Q is split longitudinally into threesegments, as shown in Figures 2 and 3, eachsegment being Welded on toabout one third of the strands of the flexible composite cable conductorA. The bolt M fits into the bore of the contact plug, is threaded at oneend to receive the nut N, and is shaped at the other end (i. e. the headof the bolt) to fit the taper of the bore. The nut N is also shaped tofit the taper at the other end of the bore and is provided with anair-hole D to allow escape of air on tightening the nut. To assemble theconnector the nut N is screwed one or two turns on to the bolt M, andthe combined nut and bolt is inserted between the opened-out segments ofthe contact plug with the head of the bolt towards the ends of thesegments which are welded on to the flexible composite cable conductorA. The segments are closed up and the plug is inserted into the contactsleeve 0. The nut N is tightened on to the bolt M, and as the two arescrewed together the segments of the contact plug, by virtue of thetapers on the nut and bolt acting on the tapers in the bore, are forcedoutwards against the inner surface of contact sleeve 0, thereby makingthe electrical connection.

The dimensions of the electrical connector can vary according to thepurpose for which it is intended, and the approximate size of connectorneeded to carry any particular electrical current can readily bedetermined by one skilled in the art. The electrical connector isconstructed of any suitable conducting material, e. g. metals such assteel, copper, brass and the like; the exact materials for a connectorneeded to carry any particular electrical current may readily bedetermined by one skilled in the art.

The electrical connector as illustrated in Figures 1 and 2 can bemodified in many ways without departing from the principle of theinvention. 'Thus although it is convenient to construct the contactsleeve 0, as a cylindrical member, it may also be formed in a number ofothercross-sectional' shapes, preferably regular in pattern, e. g.square, pentagonal, hexagonal, etc. To obtain the most effectiveelectrical connection the contact plug Q must fit closely inside thecontact sleeve; the optimum external shape of the plug is thereforedetermined by the internal shape of the contact sleeve. The bore of thecontact plug Patented Nov. 4, 1958 in Figure lis made square, thetapering head of thebolt M has also to be made square to conform withthe bore. This arrangement has the advantage that the bolt cannot turnwhen the nut N is being screwed or unscrewed. Alternatively; in the caseof a bore of circular cross-sec? tion as shown in Figures 1 and 2, thehead of the boltM may have-a lug- S which fits into a recess U in thewall of the contact plugto prevent the bolt revolving. The angle ordegree of taper in the bore of the contact plug is also not critical.

leverage exerted on the contact plug and the greater will be thepressure-exerted bythe contact plug against the inner surface of thecontact sleeve. The optimum angle of taper for any particular electricalconnection can readily be determined by askilled engineer.

The number of'longitudinal segments into which the contact plugis-splitmay be two or more. It is preferred to use a contact plug splitinto three segments.

A second embodiment: of the invention is illustrated in Figures 4 and 5.In this embodiment the contact plug Q issplitlongitudinally into foursegments and has a longitudinal bore of square cross-section throughoutits length which tapers from each end towards the centre. Two taperedmembers D are shaped to fit into the bore at either end and are threadedinternally, one with a left hand thread and the other with a right handthread. The stud M is provided with left hand threads at one end andright hand threads at the other. When the stud M is turned by means ofthe square head F, the tapered members D are drawn together, or forcedapart, depending on which way the stud is turned, the electricalconnector being tightened or loosened accordingly.

Arpreferred embodiment of the invention is illustrated in Figureso, 7and 8 which show a water-cooled connector for connecting a rigid tubularconductor E with a hollow flexiblecomposite cable A, surrounded by aflexible corrugated metal sheath B. The connector consists bore of thecontact plug. The contact sleeveO, is screwed into and weldedi to anelbow member B, one armof which is connected by means of a threadedjoint. tothe rigiditubular conductor E, while the other arm is joined.

to the flexible corrugated metal sheath B. Thejointbetween the elbowmember P and the sheath Bi isrnade by means of the flange I, which issoldered around the sheath. The flange is pulled, tightly against theelbow member by means of the nut K, and the joint is; made watertight bymeans of a gasket L, e. g. of siliconerubber, inserteclin a recess ofthe flange I. They cooling water passes through the tubular conductorE,. circulates around the connector portion of the assembly, and passesthrough the flexible sheath B, by arrows W, both insideand outside ofthe hollow flexible cable A. Leakage of cooling water up the contactsleeve pastthe nut N is= prevented by means of the screw cap R.

The assembly and dismantling of the connector are facilitated by. thehole, G, which passes throughythecontactplug Qand through the boltM. Onassemblingthe connector, the bolt M is located alongtheaxis of. the con-However, it will be apparent that, the flatter the angle of the taperthe greater will be the tact plug Q and is held in position by passing alocating pin into the hole G, through both the contact plug and thebolt. The contact plug is then inserted into the contact sleeve 0, andthe nut N is screwed on to the small end of the bolt. After partiallytightening the nut the locating pin is removed and the nut furthertightened. To dismantle the connector it is convenient, particularlywhen the connector has been in position for some time and may be firmlyfixed due to deposition fromthe cooling water, to loosen the nut Nsomewhat, to insert the locating pin through the contact plug and boltat G and to tap the head of the nut so as to drive the contact plug outof the contact sleeve.

The assembly and dismantling of the connector are also facilitated bythe use of thethreaded recess H in the bolt M in Figure 6. A screwthreaded pin can be inserted into recess H as a means of preventing thebolt M from slipping down out of reach while the nut N is being screwedon.

I claim:

1. An electrical, connector for connecting. two com ductors at least oneof which is a flexible composite cable conductor which comprises acontact sleeve, mean forming part of said contact sleeve for attachingsaid sleeve to one of the conductors, a contact plug fittingcloselyinside. the contact sleeve, the contact plug having an un:

threaded longitudinal bore which tapers from each end' when in positionin the bore whereby the segmentssofthe.

contact plug are forced outwards against the inner surzface of thecontact leeve, thereby making the electrical: connection.

2. An electrieal connector-as claimedinclairn'lwherew in the contactsleeve is cylindrical.

3. An electrical connector as'rclaimed inclaiml where-- in the bore ofthe contactiplug. is circular in cross-section;

4. An electrical connector'as claimed in claiml where-- in thecontactplug: is splitiintothree-segments.

5; An electricaltconnector, as clairned in claim l where in. thefirst;tapered member comprisesa bolt threaded at" one end toreceive a nut. andshaped at the other end to fit the taper at one end of the bore, andwherein thesec ond tapered member comprises a nut adapted to bescrewedon to the bolt.

6. An electrical connectoras claimed'in claimj'wherein the nut comprisesa tapered portion and a head portion, the headportion being configuredfor co-operation with a turning tool.

7. An electrical connector as claimed-in claim 5' wherein the head ofthe bolt is provided with a lug, said-con tact plug having a recess inthe wall thereof into which said lug fits.

8. An electrical connector as claimed in claim 5' wherein the bolt hasa. transverse passage which corresponds, when the bolt is in positioninthe connector, with a transverse passage through the portion of thecontactplug not enclosed bythe contact sleeve, whereby a tool can bepassed through a passage in the contact plug and through the bolt.

9; An electrical connector as claimed in claim 5 wherein the-threadedend of the bolt is provided with a longitudinal threaded recess, wherebythe threaded end' of a tool can bepassed through the nut and screwedinto the threaded recess.

10. An electrical connector as claimed in claim 1 wherein the contactplug issplit into four segmentsand. has a bore of square cross-section,wherein the two tapered members are threaded internally one with arighthand thread and the other with a left-hand thread, and wherein themeans for screwing the two tapered members together comprises a studwith right-hand threads at one end and left-hand threads at the otherend, whereby turning the stud in position screwed into the two taperedmembers causes the tapered members to be drawn together or apart.

References Cited in the file of this patent UNITED STATES PATENTSPortrnan Sept. 28, 1915 Kilian Aug. 15, 1933 Gelpcke May 8, 1934 ThackerFeb. 14, 1950 Capita Apr. 22, 1952 Behinke et a1. Aug. 3, 1954

